Follow-up to Keyframes not visible with object selected
In short, keyframes disappeared from the timeline without losing effect, and previous solutions aren't restoring them to view.
I have attempted the following suggestions so far:
Select object and node property sequentially
Disable "Only Keyframes from Selected Channels" in Timeline Editor View menu
Assure "Only Show Errors" is disabled
Middle click and drag in the timeline to attempt to move keyframes in view
Press the home key/click "Frame All" in the Timeline Editor
Unfortunately, none of these suggetions worked. I am providing my *.blend file.
The properties in question are color stop positions in the selected ColorRamp node in the object labeled "GHOST KEYFRAMES OBJECT".